Microbiome Assembly of Phyllody-Infected Sesame Leaves

Sesame phyllody disease poses a serious threat to sesame cultivation, often leading to complete crop failure due to the absence of resistant varieties and lack of effective chemical treatments. To explore sustainable alternatives, this study investigated the foliar microbiome by comparing microbial communities in healthy and phyllody-infected sesame plants from severely affected fields. Through combined culture-based techniques and DNA sequencing, we identified 3108 bacterial OTUs spanning several key genera, including Pantoea, Pseudomonas, Allorhizobium, and Xanthomonas. Phytoplasma, the known causal agent, was detected exclusively in symptomatic plants. Co-occurrence network analysis revealed distinct microbial associations: healthy plants showed balanced interactions with Pantoea, Pseudomonas, and Sphingomonas as central hubs, whereas infected plants exhibited a denser, more complex network, indicating phytoplasma-driven shifts in microbial structure. From culturable isolates, 72 bacterial strains were recovered, with Pantoea being predominant in both plant types. Functional predictions highlighted microbial association with nutrient metabolism and biosynthesis of alpha-linolenic acid, a naturally abundant compound in sesame. This first study of the sesame foliar microbiome provides valuable insights into plant-microbiome-phytoplasma interactions and lays a foundation for developing microbiome-based, eco-friendly strategies to manage sesame phyllody disease in the future.